A known one of such crawler-type traveling vehicles is designed to be capable of a forward and backward straight travel, a slalom turn, a pivot turn and a spin turn by controlling the revolving directions and velocities of the transversely opposite crawler travel devices in accordance with the directions and amounts of operation on transversely opposite two travel operation levers (see Japanese Laid-Open Patent Publication No. 2003-343510(A) for example). Another known crawler-type traveling vehicle includes, instead of the transversely opposite two travel operation levers, a travel operation device having a travel lever for switching between a forward travel and a backward travel, an accelerator pedal for setting a traveling velocity, and a steering wheel for setting a turning direction and a turning amount (see Japanese Laid-Open Utility Model Publication No. H5-24481(A) for example). Yet another known crawler-type traveling vehicle includes a joystick-type travel operation device which is capable of setting a forward travel, a backward travel, a traveling velocity, a turning direction and a turning amount by means of a single travel operation lever (see Japanese Laid-Open Patent Publication No. 2002-104227(A) for example).